Philadelphia -LRB- CNN -RRB- -- Andrew Cattaneo is still in shock .

It 's been only a day since his neighbor across the street , Melissa Ketunuti , was found dead in the basement of her row home Monday afternoon , her hands and feet bound , her body set on fire .

Standing in the doorway of his home , Cattaneo watched as police detectives returned to the scene Tuesday while news reporters huddled nearby trying to stay warm on the blustery January afternoon .

`` She was very pleasant , very nice , very friendly and quiet , '' Cattaneo said , looking across the street . `` It 's very upsetting . ''

Although authorities were awaiting the final autopsy report , Philadelphia Police Capt. James Clark , homicide commanding officer , said at a news conference Tuesday morning that Ketunuti , a 35-year-old physician , apparently was strangled . There were no immediately obvious signs of sexual assault , Clark said .

Ketunuti lived alone with her dog Pooch on a quiet , narrow and tree-lined street in Philadelphia 's Center City . It was her dog walker , police said , who discovered her smoldering body .

The investigation is ongoing , Clark said , and the motive for her death is unclear . Police continued to canvass the neighborhood Tuesday in search of surveillance video .

Police say Ketunuti stopped at several stores Monday before making her way home , and there were no signs of struggle , indicating that she may have been followed .

`` We do n't know if she walked in on individuals inside of her property , we do n't know if individuals forced her inside her property , or whether or not she knew her killer , '' Clark said . `` We 're not closing any avenues . ''

In 2008 , Ketunuti moved from Washington to Philadelphia , where she was a pediatrics resident at the Children 's Hospital of Philadelphia .

`` This is hopefully the last move for at least 3 years , given that 's how long it should take to finish a pediatrics residency , '' she penned on her personal online blog where she chronicled her globe-trekking adventures and updated her progress with school .

`` As sexy as it was to be a life-saving surgeon , I feel much better suited for pediatrics , '' she wrote . Her postings referred to a surgery internship at Georgetown University Hospital in Washington , and a second internship in cardiothoracic surgery at a veterans hospital .

Across the street from Ketunuti 's house , another neighbor who did not want to be identified was visibly upset at the news of her death .

`` Who would want to do this ? '' the neighbor said .

The neighbor described Ketunuti as a private person , but not unfriendly .

`` I 'm struggling for the logic to why my friend is dead , '' the neighbor said , fighting back tears . `` I 'm sick with this . ''

The neighbor said Ketunuti was often seen running long distances , and returning home with groceries , that she had very few visitors , and that Ketunuti spent a significant amount of time at the hospital .

That was a point reiterated by police .

`` She dedicated her whole life to being a doctor and helping kids with cancer , '' Clark said . `` It 's very unfortunate that she died in this manner . ''

Ketunuti graduated with a doctorate in medicine from Stanford University in 2007 . Over the years , she completed a clerkship in Botswana , as well as internships at New York University and Johns Hopkins , she wrote on her blog .

No arrests had been made or suspects identified in the case as of Tuesday , according to police , and there is a $ 20,000 reward for arrest and conviction in relation to the killing .

Children 's Hospital of Philadelphia released a statement Tuesday afternoon saying Ketunuti was a second-year infectious diseases fellow and researcher . She had been at the hospital for five years , the statement said , and had also served as a resident in the Department of Pediatrics .

`` Melissa was a warm , caring , earnest , bright young woman with her whole future ahead of her , '' Dr. Paul Offit , chief of the hospital 's division of infectious diseases , said in an e-mail statement .

`` But more than that , she was admired , respected and loved by those with whom she worked here ... Her death will have a profound impact on those who worked with her and we will all miss her deeply . ''

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Melissa Ketunuti was a doctor at Children 's Hospital of Philadelphia

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She was found dead at her home Monday

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Her hands and feet had been bound , and her body was set on fire

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`` Who would want to do this ? '' asks a distraught neighbor